This invention is directed to a method and system which minimizes the possibility of interference between two or more wireless RF systems which share a predetermined group of frequencies. This invention is especially, but not exclusively, suited for applications where a second RF system is allowed to share frequencies previously assigned to a first RF system.
The efficient use of available RF spectrum becomes an increasingly important concern as additional communication demands increase. Most governments utilize a regulatory agency to control the allocation of RF spectrum to users. In the United States, AM, FM, and television stations are assigned frequencies by geographic regions to prevent substantial overlapping coverage. This permits frequencies to be reused in sufficiently separated regions.
The same strategy is utilized for commercial two way radio frequencies, that is, using geographic separation in order to achieve frequency reuse. In cellular telephone systems directive antennas are utilized to create relatively small geographic cells resulting in frequencies being available for reuse in smaller areas.
There exists a need to provide even greater spectral efficiencies by permitting a second communication service to utilize a range of frequencies previously assigned for the exclusive use of a first communication service. In order to avoid RF interference problems between the first and second services, the second assigned service may be required to minimize the possibility of interference to the first service.